Alaska, Arizona, Idaho, North Carolina, West Virginia and Wyoming were added to the list on Saturday, a week after Holder made a similar announcement concerning seven other states.
The move comes after the U.S. Supreme Court declined to hear appeals of cases that sought to overturn bans on same-sex marriages. In addition to the 32 states, gay marriages are recognized in the District of Columbia.
The Justice Department's stand on the unions means the couples qualify for benefits administered by the Social Security Administration, the Department of Veterans Affairs and other federal entities.
"We are acting as quickly as possible with agencies throughout the government to ensure that same-sex couples in these states receive the fullest array of benefits allowable under federal law," Holder said.